MLA

Buckingham, D. W. Map of the City of New Haven : from Actual Survey by D.W. Buckingham, County Surveyor. [publisher not identified], , 1849. https://collections.library.yale.edu/catalog/15675088.

APA, 6th edition

Buckingham, D. W. (1849). Map of the city of New Haven : from actual survey by D.W. Buckingham, county surveyor. [Maps]. [publisher not identified], . https://collections.library.yale.edu/catalog/15675088.